[camera] Add ability to concurrently record and stream video (flutter…

…#6290)

* Implement interface methods to allow concurrent stream and record

There will be a subsequent change to the `camera` package to make use of these implementations.

* Fix android test

* Format android_camera_test.dart

* Resolve analyze failures

* Fix version bumps

* Fix MethodChannelCameraTest

* Fix comment on FLTCam

* Add tests to confirm can't stream on windows or web

* CHANGELOG updates

* Fix analyze errors

* Fix dart analyze warnings for web

* Formatted

packages/camera/camera_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.10.1
+
+* Implements option to also stream when recording a video.
+
 ## 0.10.0+5
 
 * Fixes `ArrayIndexOutOfBoundsException` when the permission request is interrupted.

packages/camera/camera_android/android/src/main/java/io/flutter/plugins/camera/Camera.java

@@ -522,6 +522,21 @@ private void refreshPreviewCaptureSession(
     }
   }
 
+  private void startCapture(boolean record, boolean stream) throws CameraAccessException {
+    List<Surface> surfaces = new ArrayList<>();
+    Runnable successCallback = null;
+    if (record) {
+      surfaces.add(mediaRecorder.getSurface());
+      successCallback = () -> mediaRecorder.start();
+    }
+    if (stream) {
+      surfaces.add(imageStreamReader.getSurface());
+    }
+
+    createCaptureSession(
+        CameraDevice.TEMPLATE_RECORD, successCallback, surfaces.toArray(new Surface[0]));
+  }
+
   public void takePicture(@NonNull final Result result) {
     // Only take one picture at a time.
     if (cameraCaptureCallback.getCameraState() != CameraState.STATE_PREVIEW) {
@@ -731,29 +746,17 @@ private void unlockAutoFocus() {
             dartMessenger.error(flutterResult, errorCode, errorMessage, null));
   }
 
-  public void startVideoRecording(@NonNull Result result) {
-    final File outputDir = applicationContext.getCacheDir();
-    try {
-      captureFile = File.createTempFile("REC", ".mp4", outputDir);
-    } catch (IOException | SecurityException e) {
-      result.error("cannotCreateFile", e.getMessage(), null);
-      return;
-    }
-    try {
-      prepareMediaRecorder(captureFile.getAbsolutePath());
-    } catch (IOException e) {
-      recordingVideo = false;
-      captureFile = null;
-      result.error("videoRecordingFailed", e.getMessage(), null);
-      return;
+  public void startVideoRecording(
+      @NonNull Result result, @Nullable EventChannel imageStreamChannel) {
+    prepareRecording(result);
+
+    if (imageStreamChannel != null) {
+      setStreamHandler(imageStreamChannel);
     }
-    // Re-create autofocus feature so it's using video focus mode now.
-    cameraFeatures.setAutoFocus(
-        cameraFeatureFactory.createAutoFocusFeature(cameraProperties, true));
+
     recordingVideo = true;
     try {
-      createCaptureSession(
-          CameraDevice.TEMPLATE_RECORD, () -> mediaRecorder.start(), mediaRecorder.getSurface());
+      startCapture(true, imageStreamChannel != null);
       result.success(null);
     } catch (CameraAccessException e) {
       recordingVideo = false;
@@ -1073,21 +1076,10 @@ public void startPreview() throws CameraAccessException {
 
   public void startPreviewWithImageStream(EventChannel imageStreamChannel)
       throws CameraAccessException {
-    createCaptureSession(CameraDevice.TEMPLATE_RECORD, imageStreamReader.getSurface());
-    Log.i(TAG, "startPreviewWithImageStream");
-
-    imageStreamChannel.setStreamHandler(
-        new EventChannel.StreamHandler() {
-          @Override
-          public void onListen(Object o, EventChannel.EventSink imageStreamSink) {
-            setImageStreamImageAvailableListener(imageStreamSink);
-          }
+    setStreamHandler(imageStreamChannel);
 
-          @Override
-          public void onCancel(Object o) {
-            imageStreamReader.setOnImageAvailableListener(null, backgroundHandler);
-          }
-        });
+    startCapture(false, true);
+    Log.i(TAG, "startPreviewWithImageStream");
   }
 
   /**
@@ -1117,6 +1109,42 @@ public void onError(String errorCode, String errorMessage) {
     cameraCaptureCallback.setCameraState(CameraState.STATE_PREVIEW);
   }
 
+  private void prepareRecording(@NonNull Result result) {
+    final File outputDir = applicationContext.getCacheDir();
+    try {
+      captureFile = File.createTempFile("REC", ".mp4", outputDir);
+    } catch (IOException | SecurityException e) {
+      result.error("cannotCreateFile", e.getMessage(), null);
+      return;
+    }
+    try {
+      prepareMediaRecorder(captureFile.getAbsolutePath());
+    } catch (IOException e) {
+      recordingVideo = false;
+      captureFile = null;
+      result.error("videoRecordingFailed", e.getMessage(), null);
+      return;
+    }
+    // Re-create autofocus feature so it's using video focus mode now.
+    cameraFeatures.setAutoFocus(
+        cameraFeatureFactory.createAutoFocusFeature(cameraProperties, true));
+  }
+
+  private void setStreamHandler(EventChannel imageStreamChannel) {
+    imageStreamChannel.setStreamHandler(
+        new EventChannel.StreamHandler() {
+          @Override
+          public void onListen(Object o, EventChannel.EventSink imageStreamSink) {
+            setImageStreamImageAvailableListener(imageStreamSink);
+          }
+
+          @Override
+          public void onCancel(Object o) {
+            imageStreamReader.setOnImageAvailableListener(null, backgroundHandler);
+          }
+        });
+  }
+
   private void setImageStreamImageAvailableListener(final EventChannel.EventSink imageStreamSink) {
     imageStreamReader.setOnImageAvailableListener(
         reader -> {

packages/camera/camera_android/android/src/main/java/io/flutter/plugins/camera/MethodCallHandlerImpl.java

@@ -26,6 +26,7 @@
 import io.flutter.view.TextureRegistry;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Objects;
 
 final class MethodCallHandlerImpl implements MethodChannel.MethodCallHandler {
   private final Activity activity;
@@ -118,7 +119,9 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull final Result result)
         }
       case "startVideoRecording":
         {
-          camera.startVideoRecording(result);
+          camera.startVideoRecording(
+              result,
+              Objects.equals(call.argument("enableStream"), true) ? imageStreamChannel : null);
           break;
         }
       case "stopVideoRecording":

packages/camera/camera_android/example/integration_test/camera_test.dart

@@ -245,4 +245,44 @@ void main() {
       await controller.dispose();
     },
   );
+
+  testWidgets(
+    'recording with image stream',
+    (WidgetTester tester) async {
+      final List<CameraDescription> cameras =
+          await CameraPlatform.instance.availableCameras();
+      if (cameras.isEmpty) {
+        return;
+      }
+
+      final CameraController controller = CameraController(
+        cameras[0],
+        ResolutionPreset.low,
+        enableAudio: false,
+      );
+
+      await controller.initialize();
+      bool isDetecting = false;
+
+      await controller.startVideoRecording(
+          streamCallback: (CameraImageData image) {
+        if (isDetecting) {
+          return;
+        }
+
+        isDetecting = true;
+
+        expectLater(image, isNotNull).whenComplete(() => isDetecting = false);
+      });
+
+      expect(controller.value.isStreamingImages, true);
+
+      sleep(const Duration(milliseconds: 500));
+
+      await controller.stopVideoRecording();
+      await controller.dispose();
+
+      expect(controller.value.isStreamingImages, false);
+    },
+  );
 }

packages/camera/camera_android/example/lib/camera_controller.dart

@@ -306,11 +306,14 @@ class CameraController extends ValueNotifier<CameraValue> {
   ///
   /// The video is returned as a [XFile] after calling [stopVideoRecording].
   /// Throws a [CameraException] if the capture fails.
-  Future<void> startVideoRecording() async {
-    await CameraPlatform.instance.startVideoRecording(_cameraId);
+  Future<void> startVideoRecording(
+      {Function(CameraImageData image)? streamCallback}) async {
+    await CameraPlatform.instance.startVideoCapturing(
+        VideoCaptureOptions(_cameraId, streamCallback: streamCallback));
     value = value.copyWith(
         isRecordingVideo: true,
         isRecordingPaused: false,
+        isStreamingImages: streamCallback != null,
         recordingOrientation: Optional<DeviceOrientation>.of(
             value.lockedCaptureOrientation ?? value.deviceOrientation));
   }
@@ -319,10 +322,15 @@ class CameraController extends ValueNotifier<CameraValue> {
   ///
   /// Throws a [CameraException] if the capture failed.
   Future<XFile> stopVideoRecording() async {
+    if (value.isStreamingImages) {
+      await stopImageStream();
+    }
+
     final XFile file =
         await CameraPlatform.instance.stopVideoRecording(_cameraId);
     value = value.copyWith(
       isRecordingVideo: false,
+      isRecordingPaused: false,
       recordingOrientation: const Optional<DeviceOrientation>.absent(),
     );
     return file;

packages/camera/camera_android/example/pubspec.yaml

@@ -14,7 +14,7 @@ dependencies:
     # The example app is bundled with the plugin so we use a path dependency on
     # the parent directory to use the current plugin's version.
     path: ../
-  camera_platform_interface: ^2.2.0
+  camera_platform_interface: ^2.3.1
   flutter:
     sdk: flutter
   path_provider: ^2.0.0

packages/camera/camera_android/lib/src/android_camera.dart

@@ -248,13 +248,25 @@ class AndroidCamera extends CameraPlatform {
   @override
   Future<void> startVideoRecording(int cameraId,
       {Duration? maxVideoDuration}) async {
+    return startVideoCapturing(
+        VideoCaptureOptions(cameraId, maxDuration: maxVideoDuration));
+  }
+
+  @override
+  Future<void> startVideoCapturing(VideoCaptureOptions options) async {
     await _channel.invokeMethod<void>(
       'startVideoRecording',
       <String, dynamic>{
-        'cameraId': cameraId,
-        'maxVideoDuration': maxVideoDuration?.inMilliseconds,
+        'cameraId': options.cameraId,
+        'maxVideoDuration': options.maxDuration?.inMilliseconds,
+        'enableStream': options.streamCallback != null,
       },
     );
+
+    if (options.streamCallback != null) {
+      _installStreamController().stream.listen(options.streamCallback);
+      _startStreamListener();
+    }
   }
 
   @override
@@ -290,13 +302,19 @@ class AndroidCamera extends CameraPlatform {
   @override
   Stream<CameraImageData> onStreamedFrameAvailable(int cameraId,
       {CameraImageStreamOptions? options}) {
+    _installStreamController(onListen: _onFrameStreamListen);
+    return _frameStreamController!.stream;
+  }
+
+  StreamController<CameraImageData> _installStreamController(
+      {Function()? onListen}) {
     _frameStreamController = StreamController<CameraImageData>(
-      onListen: _onFrameStreamListen,
+      onListen: onListen ?? () {},
       onPause: _onFrameStreamPauseResume,
       onResume: _onFrameStreamPauseResume,
       onCancel: _onFrameStreamCancel,
     );
-    return _frameStreamController!.stream;
+    return _frameStreamController!;
   }
 
   void _onFrameStreamListen() {
@@ -305,6 +323,10 @@ class AndroidCamera extends CameraPlatform {
 
   Future<void> _startPlatformStream() async {
     await _channel.invokeMethod<void>('startImageStream');
+    _startStreamListener();
+  }
+
+  void _startStreamListener() {
     const EventChannel cameraEventChannel =
         EventChannel('plugins.flutter.io/camera_android/imageStream');
     _platformImageStreamSubscription =

packages/camera/camera_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_android
 description: Android implementation of the camera plugin.
 repository: https://github.com/flutter/plugins/tree/main/packages/camera/camera_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.10.0+5
+version: 0.10.1
 
 environment:
   sdk: ">=2.14.0 <3.0.0"
@@ -18,7 +18,7 @@ flutter:
         dartPluginClass: AndroidCamera
 
 dependencies:
-  camera_platform_interface: ^2.2.0
+  camera_platform_interface: ^2.3.1
   flutter:
     sdk: flutter
   flutter_plugin_android_lifecycle: ^2.0.2

packages/camera/camera_android/test/android_camera_test.dart

@@ -587,6 +587,7 @@ void main() {
         isMethodCall('startVideoRecording', arguments: <String, Object?>{
           'cameraId': cameraId,
           'maxVideoDuration': null,
+          'enableStream': false,
         }),
       ]);
     });
@@ -609,7 +610,33 @@ void main() {
       expect(channel.log, <Matcher>[
         isMethodCall('startVideoRecording', arguments: <String, Object?>{
           'cameraId': cameraId,
-          'maxVideoDuration': 10000
+          'maxVideoDuration': 10000,
+          'enableStream': false,
+        }),
+      ]);
+    });
+
+    test(
+        'Should pass enableStream if callback is passed when starting recording a video',
+        () async {
+      // Arrange
+      final MethodChannelMock channel = MethodChannelMock(
+        channelName: _channelName,
+        methods: <String, dynamic>{'startVideoRecording': null},
+      );
+
+      // Act
+      await camera.startVideoCapturing(
+        VideoCaptureOptions(cameraId,
+            streamCallback: (CameraImageData imageData) {}),
+      );
+
+      // Assert
+      expect(channel.log, <Matcher>[
+        isMethodCall('startVideoRecording', arguments: <String, Object?>{
+          'cameraId': cameraId,
+          'maxVideoDuration': null,
+          'enableStream': true,
         }),
       ]);
     });

packages/camera/camera_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.9.9
+
+* Implements option to also stream when recording a video.
+
 ## 0.9.8+6
 
 * Updates code for `no_leading_underscores_for_local_identifiers` lint.